All organisms are made of cells

2. All organisms are made of cells Cells conform to the definition of life

3. Reproduce Change with time Highly organized CELLS… • Obtain energy and materials from their food • Respond to their environments

4. 1595 credited to Zacharias Janssen eyeglasses beginning to be used; lots of focus & great deal of attention to optics and lenses probably helped by his father Hans slide the draw tube in or out while observing the sample magnifying images approximately three times when fully closed and up to ten times when extended to the maximum Invention of the compound Microscopes

6. First Living Cells • Discovered by Anton von Leewenhoek • Dutch drapery store owner • FIRST to OBSERVE and DESCRIBE MICROSCOPIC ORGANISMS and LIVING CELLS • Teeth scrapings— “animacules”

7. Robert Hooke: Cork Cells • 1665 • English Scientist • thin slice of cork and • "a great many little boxes" • reminded him of the small rooms in which monks lived, so he called them: "Cells"

8. 1838: German Botanist Schleiden 1839: German Zoologist Schwann 1855: German Physician Virchow studied a variety of PLANTS and concluded that all PLANTS "ARE COMPOSED OF CELLS“ reported that ANIMALS are also made of CELLS and proposed a cellular basis for all life. induced that “The animal arises only from an animal and a plant only from a plant” or “cells only come from other cells.” To the cell theory…

9. Cell Theory Summary of Schleiden, Schwann, & Virchow • All organisms are composed of one or more cells—life processes occur here. • Cells are the basic unit of structure and function of all organisms. 3. All cells come from other cells.

10. Spontaneous Generation Cell Theory • Went against the idea that life could arise from nonliving matter • Redi—fly/meat experiment • Pasteur—broth experiment

11. All cells share three common features… • PLASMA MEMBRANE (cell membrane) is cell’s boundary • separates the inside from the rest of the world • highly organized and responsive • regulates the cell’s environment by selecting what enters and leaves (like a gated community)

12. 2. GENETIC INFORMATION for each cell are contained in molecules of DNA • Eukaryotes • Prokaryotes 3. CYTOPLASM • outside the nucleus but inside the membrane

13. The shape of a cell depends on it’s function

14. The cell’s need to regulate its internal environment limits its size • Homeostatic regulation of salt concentration and pH • take in useful molecules and dispose of waste

15. Large cells Difficult to maintain just the right environment for all of the different molecular activities • This is why most unicellular organisms are microscopic.

16. Limits to cell size • Limited by the RATIO between their Outer Surface Area and Their Volume.  • A SMALL CELL HAS MORE SURFACE AREA THAN A LARGE CELL FOR A GIVEN VOLUME OF CYTOPLASM.  • nutrients, oxygen, and other materials a cell requires must enter through it surface

17. The cell’s nucleus (the brain) can only control a certain amount of living, active cytoplasm.

18. How Big Are Cells?

19. Prokaryotic cells: Bacteria • Prokaryote: before the nucleus • Cytoplasm—all metabolism here • No membrane-bound organelles • DNA—circular & not in a nucleus • Cell wall, cell membrane, ribosomes, nucleoid region

21. Eukaryotic Cells • “true” “nut” • Nucleus • Membrane-bound organelles • Specialized structures • subdivided

22. Cellular organization has two important benefits • allows organisms to make a division of labor among specialized cells • allows organisms to outlive the cells that compose them

23. Nucleus • contains genetic instructions for how to make a new cell • Nuclear membrane: controls the movement of materials in and out of the nucleus • Nuclear Pores

25. Genetic Information • coded in DNA and is passed from one generation to the next • chromosomes are composed of chromatin, a complex of DNA and protein • chromosomes are formed when the cell is dividing

26. Cytoplasm—from the membrane to the nucleus and all the “stuff in between” cytosol—the Jell-O like part of the inside of a cell where most of the work of the cell is done Cytoplasm/Cytosol

27. cytosol makes up 50% of the cell’s volume • contains enzymes important to • building molecules • breaking small molecules • making proteins • also contains glycogen and fat • organelles, vesicles, and vacuoles embedded within

28. Endoplasmic reticulum • ER is continuous from the nucleus • Rough or smooth • modifies proteins—especially those being exported from the cell • cells specialized for the production of secreted proteins have large amounts of rough ER

30. Ribosomes • ribosomes are complexes of RNA and protein (found in cytosol) • tiny, round organelles for protein synthesis • “free ribosomes” • and ER bound • ribosomes

31. Smooth ER • Ribosome-free • synthesize and metabolize lipids • detoxifies alcohol • produce steroid hormones

32. packages and labels proteins for destinations inside/outside the cell usually near the nucleus # of golgi complexes varies Found in cells that secrete lots of proteins (esp. exported) golgi packages them into membrane-bound vesicles Golgi Complex or Bodies

33. Up to 100 a cell!!!

34. Golgi Apparatus at Work

35. Packaging Proteins

36. Lysosomes • digest wastes and foreign invaders • made in Golgi apparatus • the lysosome’s membrane keeps it from digesting the cytosol vary in size but all contain enzymes to break down proteins, nucleic acids, sugars, lipids

37. use oxygen to break down molecules that produce hydrogen peroxide H2O2 is bad for the cell; kept inside Another enzyme breaks down the hydrogen peroxide into water and oxygen Found in cells that synthesize, store, or break down lipids Peroxisomes Can occupy half the volume of the cell

38. Mitochondria • Capture the energy from small organic molecules and convert it into the form of ATP • ATP provides the power to fuel the cell’s chemical reactions • Outer membrane is smooth; inner is folded (cristae) Cells that use a lot of energy have lots of mitochondria

40. Chloroplasts • chloroplasts—site of photosynthesis where sugars are made and stored; large, round, green (chlorophyll) • Chromoplasts--pigments • turn solar energy into chemical energy through photosynthesis • Type of plastid--plant organelle that is surrounded by a double membrane

42. Vacuoles • Large membrane-bound sacs without any obvious internal structure • Type of vesicle • vacuoles up to 95% of cell’s volume

43. network of protein filaments give structure and support to the cytoplasm and its organelles provides the force for most of the cellular movement and is constantly dissolving and reforming Cytoskeleton skeletal and muscular system for the cell

45. Centrosomes/Centrioles Help animal cells do that mitosis thing…you know where they divide and stuff.

46. Asymmetrical phospholipid bilayer hydrophobic tail & hydrophilic head phospholipids arranged head to tail proteins throughout; contribute to structure and function Plasma Membrane

47. Membranes’ 4 major roles 4. workbench for biochemical reactions—metabolizing of lipids and secretion of proteins • separate the inside from the outside • regulate the contents of the spaces they enclose • energy conversions

49. hydrophobic barrier, confining hydrophilic molecules to the inside or the outside of a cell • some membrane proteins help transport specific molecules across the membrane • It is fluid—proteins and lipids can move freely along the plain of the membrane

50. Cell Wall • Plant cells • Cellulose (polysaccharides) • Supports!! Rigid!! • Protects!! • Does it allow materials to pass into/out of the cell? • Also bacteria, fungus, some Protista